Revealing the Grammar of Small RNA Secretion Using Interpretable Machine Learning II
Ontology highlight
ABSTRACT: Small non-coding RNAs can be secreted through a variety of mechanisms, including exosomal sorting, in small extracellular vesicles, and within lipoprotein complexes. However, the mechanisms that govern their sorting and secretion are still not well understood. In this study, we present ExoGRU, a machine learning model that predicts small RNA secretion probabilities from primary RNA sequence. We experimentally validated the performance of this model through ExoGRU-guided mutagenesis and synthetic RNA sequence analysis, and confirmed that primary RNA sequence is a major determinant in small RNA secretion. Additionally, we used ExoGRU to reveal cis and trans factors that underlie small RNA secretion, including known and novel RNA-binding proteins, e.g., YBX1, HNRNPA2B1, and RBM24. We also developed a novel technique called exoCLIP, which reveals the RNA interactome of RBPs within the cell-free space. We used exoCLIP to reveal the RNA interactome of HNRNPA2B1 and RBM24 in extracellular vesicles. Together, our results demonstrate the power of machine learning in revealing novel biological mechanisms. In addition to providing deeper insight into complex processes such as small RNA secretion, this knowledge can be leveraged in therapeutic and synthetic biology applications.
Project description:Small non-coding RNAs can be secreted through a variety of mechanisms, including exosomal sorting, in small extracellular vesicles, and within lipoprotein complexes. However, the mechanisms that govern their sorting and secretion are still not well understood. In this study, we present ExoGRU, a machine learning model that predicts small RNA secretion probabilities from primary RNA sequence. We experimentally validated the performance of this model through ExoGRU-guided mutagenesis and synthetic RNA sequence analysis, and confirmed that primary RNA sequence is a major determinant in small RNA secretion. Additionally, we used ExoGRU to reveal cis and trans factors that underlie small RNA secretion, including known and novel RNA-binding proteins, e.g., YBX1, HNRNPA2B1, and RBM24. We also developed a novel technique called exoCLIP, which reveals the RNA interactome of RBPs within the cell-free space. We used exoCLIP to reveal the RNA interactome of HNRNPA2B1 and RBM24 in extracellular vesicles. Together, our results demonstrate the power of machine learning in revealing novel biological mechanisms. In addition to providing deeper insight into complex processes such as small RNA secretion, this knowledge can be leveraged in therapeutic and synthetic biology applications.
Project description:Small non-coding RNAs can be secreted through a variety of mechanisms, including exosomal sorting, in small extracellular vesicles, and within lipoprotein complexes. However, the mechanisms that govern their sorting and secretion are still not well understood. In this study, we present ExoGRU, a machine learning model that predicts small RNA secretion probabilities from primary RNA sequence. We experimentally validated the performance of this model through ExoGRU-guided mutagenesis and synthetic RNA sequence analysis, and confirmed that primary RNA sequence is a major determinant in small RNA secretion. Additionally, we used ExoGRU to reveal cis and trans factors that underlie small RNA secretion, including known and novel RNA-binding proteins, e.g., YBX1, HNRNPA2B1, and RBM24. We also developed a novel technique called exoCLIP, which reveals the RNA interactome of RBPs within the cell-free space. We used exoCLIP to reveal the RNA interactome of HNRNPA2B1 and RBM24 in extracellular vesicles. Together, our results demonstrate the power of machine learning in revealing novel biological mechanisms. In addition to providing deeper insight into complex processes such as small RNA secretion, this knowledge can be leveraged in therapeutic and synthetic biology applications.
Project description:Small non-coding RNAs can be secreted through a variety of mechanisms, including exosomal sorting, in small extracellular vesicles, and within lipoprotein complexes. However, the mechanisms that govern their sorting and secretion are still not well understood. In this study, we present ExoGRU, a machine learning model that predicts small RNA secretion probabilities from primary RNA sequence. We experimentally validated the performance of this model through ExoGRU-guided mutagenesis and synthetic RNA sequence analysis, and confirmed that primary RNA sequence is a major determinant in small RNA secretion. Additionally, we used ExoGRU to reveal cis and trans factors that underlie small RNA secretion, including known and novel RNA-binding proteins, e.g., YBX1, HNRNPA2B1, and RBM24. We also developed a novel technique called exoCLIP, which reveals the RNA interactome of RBPs within the cell-free space. We used exoCLIP to reveal the RNA interactome of HNRNPA2B1 and RBM24 in extracellular vesicles. Together, our results demonstrate the power of machine learning in revealing novel biological mechanisms. In addition to providing deeper insight into complex processes such as small RNA secretion, this knowledge can be leveraged in therapeutic and synthetic biology applications.
Project description:Extracellular vesicles (EVs) are cell-secreted membranous particles contributing to intercellular communication. Coding and non-coding RNAs are widely detected as EV cargo, and RNAbinding proteins (RBPs), such as hnRNPA2B1, have been circumstantially implicated in EV-RNA sorting mechanisms. However, the contribution of competitive RBP-RNA interactions responsible for RNA-sorting outcomes is still unclear, especially for predicting the EV-RNA content. We designed a reverse proteomic analysis exploiting the EV-RNA to identify intracellular protein binders in vitro and used cells expressing a recombinant hnRNPA2B1 to normalize competitive interactions. Interestingly, we prioritized heterogeneous nuclear ribonucleoproteins in networks including RAB proteins and recognizing purine-rich RNA sequences representing a subset of previously identified EXO motifs. A screening campaign using a full-length human hnRNPA2B1 protein and a synthetic purine-rich RNA probe brought to small molecule inhibitors orthogonally validated through biochemical and cell-based approaches. Selected drugs effectively interfered with a post-transcriptional layer impacting secreted EV-RNAs, reducing the vesicular pro-inflammatory miR-221 while counteracting the hnRNPA2B1- or TDP43Q331K-dependent paracrine activation of NF-kB in EV recipient cells. These results demonstrate the relevance of post-transcriptional mechanisms for EV-RNA sorting and the possibility of predicting the EV-RNA quality for developing innovative strategies targeting discrete paracrine functions.
Project description:Exosomes are released by most cells to the extracellular environment, and are involved in cell-to-cell-communication. Exosomes contain specific repertoires of mRNAs, miRNAs and other non-coding RNAs that can be functionally transferred to recipient cells. However, the mechanisms that control the specific loading of RNA species into exosomes remain unknown. Here we describe short sequence motifs present in miRNAs that control their localization into exosomes. The protein hnRNPA2B1 specifically binds exosomal miRNAs through the recognition of these motifs and controls their loading into exosomes. Moreover, hnRNPA2B1 in exosomes is sumoylated, and sumoylation controls the binding of hnRNPA2B1 to miRNAs. The loading of miRNAs into exosomes can be modulated by mutagenesis of the identified motifs or changes in hnRNPA2B1 expression levels. These findings identify hnRNPA2B1 as a key player in miRNA sorting into exosomes and provide potential tools for the packaging of selected regulatory RNAs into exosomes and their use in biomedical applications.
Project description:The base excision repair (BER) Apurinic/apyrimidinic endonuclease 1 (APE1) enzyme is endowed with several non-repair activities, such as the cell response to genotoxic stress, the regulation of gene expression and miRNAs processing. We recently demonstrated that APE1 can be actively secreted by mammalian cells through exosomes. The role of APE1 in exosomes is still unknown, especially regarding the molecular mechanism involving small non-coding RNAs vesicular secretion. miRNAs loading into exosomes is a regulated and selective process, since not all the expressed miRNAs are indistinctly conveyed into exosomes. Through a dedicated transcriptomic analysis on cellular and vesicular small RNAs, we identified secreted miRNAs characterized by enriched sequence motifs and possible binding sites for APE1. In 50 out of 53 DE-miRNA precursors, we surprisingly found EXO motifs and proved that APE1 cooperates with hnRNPA2B1 for the EV-sorting of a subsets of miRNAs, including miR-1246, through a direct binding to GGAG stretch. We provide evidence of a new post-transcriptional role for this ubiquitous DNA-repair enzyme towards miRNAs secretion mechanisms, that could be exploited to interfere with tumor microenvironment.
Project description:In mammalian systems, extracellular small RNAs can operate in a paracrine manner to communicate information between cells, relying on transport within vesicles. “Foreign” small RNAs derived from bacteria, plants and parasites have also been detected in mammalian body fluids, sparking interest in whether these could mediate inter-species communication. However, there is no mechanistic framework for RNA-mediated interspecies communication and the active movement of RNA via vesicles has not been shown outside of mammals. Here we demonstrate that specific microRNAs and Y RNAs are packaged into vesicles secreted by a gastrointestinal nematode, Heligmosomoides polygyrus, which naturally infects mice. Total RNA was extracted from the secretion product of adult worms and compared to the profile of small RNAs in adult worms, eggs and infective larvae.